Wonderful stuff there, Andy!
I suggested earlier that, if you want, I'll happly make the board? I had some ideas. Most of these were drawn straight after the last BLAM.
I would indeed suggest that you guys do the boards (since you got a car to transport them, IIRC), and we can do some collaborative effort for the "terrain features". As said, I am not sure if I can actually make it to BLAM this year, but we could still do the project and I would send you my terrain pieces by mail if I really cannot make it. So I would focus on the rules for now, and start some small, light terrain pieces in the new year.
If you could do a rough sketch of the board layout, maybe 6x4, with one terrain feature in every square foot, and maybe a big underwater city (Atlantis?) on one of the short sides. It could be nested in an underwater mountain ridge, "forcing" the players to move across the length of the table.
Or we could designate a section of the table as "above water" (as in an air-filled cave, like the Disney Atlantis from that not-too-bad, but not-too-great film), with a submarine pen. The remainder could be "underwater" terrain.